it's unlikely it does anything.
RPG In A Box supporting BB code is a bit of an accident, in the sense that it's not designed to or supposed to, but in some cases it will work.
For example, [color=#hexcode] can be used to change text color.
Justin did not add that ability into this software, RPG In A Box just does it because Godot does it.
But most BB code isn't supported in Godot 3.5, or whichever build RPGiaB is running on, so most don't work at all, or do something unexpected.
for example, [b] will just make the text smaller instead of bold.
For that reason I doubt [url] is implemented or works at all, and certainly won't support inengine custom function names or script names as url's.
These various font commands are a part of Godot 4 so once we're using RPGiaB 2.0 we'll be able to use all the font formattin codes, and that might very possibly include url.
If you want to make a bit of your text click able to do something...the best thing is to put a unbordered/non-background button between two text labels to give it the appearance of just being text but in reality it's a button.
